Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Sep. 30, 2017	Sep. 30, 2016
Earnings (Loss) Per Common Share
Net income (loss) attributable to Lannett Company, Inc	$ 13,257	$ (29,408)
Basic weighted average common shares outstanding	36,992,064	36,699,267
Effect of potentially dilutive options and restricted stock awards	738,592
Diluted weighted average common shares outstanding	37,730,656	36,699,267
Earnings (loss) per common share attributable to Lannett Company, Inc.:
Basic (in dollars per share)	$ 0.36	$ (0.80)
Diluted (in dollars per share)	$ 0.35	$ (0.80)
Anti-dilutive shares excluded in the computation of diluted earnings per share	3,000,000	4,300,000

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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